Fermi Paradox

[Green Baron]

17 minutes ago, magnemoe said:

Main issue would be oxygen in atmosphere. On the other hand the early stuff on earth was not very efficient. 
On the gripping hand something good is probably part of somebody development project. 
Tips, signs and broadcasts demanding hard hats and protective boots indicate planet under construction 

I agree with the oxygen, though that is an extrapolation from earth

No, Slartibartfast was not involved. I'm sure :-)

Edited June 22, 2016 by Green Baron

[magnemoe]

Just now, Green Baron said:

Hi,

well, i must admit i can't imagine it's hard to imagine the diversity without sex. It's helpful :-)

I doubt whether sexual selection prefers the intelligent. It rather prefers the strong males and pretty female, things that today are highly influenced by cultural criteria. In times when population was thinner and people wandered in tribes it's more probabel that mixture between other groups was favored. The guys and gals of the other tribe must have been sexier than the ones they saw every day. It is assumed that in interglacials in the european ice age tribes met from to time to exchange their members and thus genome. In high glacial times they went through genetic bottlenecks. (Africa was different)

There is a misunderstanding: assuming that peace came with diversion and domestication came out of pressure. The contrary is the case: there are no (maybe one) hint of intraspecies violence in the lower stone age (until ~15.000 before now), but with the emergence of settlement there comes battle and killing. Pressure was not the reason of domestocation, it was the outcome. There was no reason for the start of plant growing and 1000yrs later domestication. It could as well have happened 110.000yrs earlier, in the OIS 5e, when climate was even better.

 

Selection for early humans was intelligence you had to make yourself popular within the group. 
It was no war for land during the lower stone age as it was no need. It has never been a war about fresh water in England or over Ice in Russia. 
Correction, it was probably some fights but nothing who left traces. Tribal wars tend be mostly diplomacy or two predators facing each other , you show strength and the weaker one stands down.
(Fails a bit today as idiots see an lack of nuclear first strike as an weakness. correcting this is not environmental friendly) 
Another reason to start farming was the climate change at the end of the ice age.Again earth was overpopulated so you had to cheat. 

 

7 minutes ago, Green Baron said:

I agree with the oxygen, though that is an extrapolation from earth

No, Slartibartfast was not involved. I'm sure :-)

Well you might end up as the cute natives or the cheep labor. 
And yes you might end up as the surviving humans too, an tail would look nice don't you think
And no the moon sized space station with the large dish is mining tool, an actual battleship is an magnitude larger. Let us not involve them. 

[Green Baron]

This leaves Fermi aside now:

Women. First fights in europe where between late mesolithic groups and first farmers. The latter ran out of women, probably due to infections and bad nutrition and loss during birth. Isotopes show where people were born and were they died. And the collections of skeletons show men, not born near the dwellings but in the surrounding hills, their skulls penetrated by typical axes (shoelast celt). They fit like the blocks in a child's hammer-and-block game.

As to sexual selection ... ok, if you say so.

 

Edited June 22, 2016 by Green Baron
w=e

[K^2]

4 hours ago, Green Baron said:

Hm, but that would imply that there is a dataset ? I'm not sure whether this is the case.

We have a single datum, Earth, which we can and are wildly extrapolating on. I agree that it shouldn't be used in the first place, and we should be extrapolating information from data gathered from everywhere else. But we don't have any, so a non-committal shrug is about as good as anyone should be able to give.

That's not to say it's not useful to ask what would apparent silence of the stars mean if we find out one way or another. Because that's what tells us that knowing whether we really are rare in the universe is important. If it's easy for sentient life to evolve in a star system, then we are likely facing extinction from a not-yet realized threat. But if sentience just happens to be  a rare gem, we can relax a little and work on building a grand civilization.

[PB666]

http://waitbutwhy.com/2014/05/fermi-paradox.html?utm_source=share&utm_medium=facebook&utm_campaign=sm_share

 

[PB666]

Parts of this are relevant to the thread, concerning when the first life supporting galaxies appeared.

[PB666]

http://www.csmonitor.com/Science/2016/0628/Did-ancient-Earth-have-more-than-two-magnetic-poles

[Green Baron]

39 minutes ago, PB666 said:

http://www.csmonitor.com/Science/2016/0628/Did-ancient-Earth-have-more-than-two-magnetic-poles

Multiple poles is "a very old hat" :-) E.g. in times of switching ...

... aww f..., wait .... "The Christian Science Monitor" ? What is that ? You see an astonished Kerbal before you !

:-)

Edit: ... can make magentostratigraphy complicated.

Edited June 28, 2016 by Green Baron

[PB666]

http://www.sciencenewsline.com/news/2016062818520088.html

 

[RenegadeRad]

I made a post where I implied that species could be unimaginably different, I still disagree there is a paradox, the only thing which makes this a paradox is that we communicate through light, which is the fastest method we have (enlighten me if there is any other before you get ready to out irony me with arguments) which is still really, really slow for the vast universe. And then there are other things such as light years, which makes things more confusing. But the truth or common sense is this - We are slow compared to the universe. And thats why one day it will be difficult for us to explore it.

[PB666]

Then you essentially agree with me whether or not there is sentient life out there, in practicality we are only interested in sentient life that might have consequences to us or us to them, lets get a time frame of 100,000 years since that is how old our species is (practically speaking). Which means that the hullabaloo about habitable planets is smoke and mirrors, it does not address the real question of tangible life in the sphere of consequences. So the reasoning here is that if light does not do alien sentiency justice on the scale of deep space, the only way to compensate is for them to move toward us or us to move toward them. Given the practical limits of space travel that essentially means at 0.1c or less, we can even cover 1/100th of our galaxy close enough to them to receive their communications, that they would have to move toward us and us toward them to cover 1/25th of the galaxy. If the density of sentiency is below 25 per our galaxy there is a 50:50 chance that our species will eventually conclude that the universe is devoid of sentient life except us.

 

 

 

[Green Baron]

The differences in the materials are probably not *that* big. Carbon, iron, oxygen, Calcium, etc. are best suited for the job. If an evolution had started elsewhere it is not out of the world to assume that it's similar to earths evolution. Other bases are imaginable (on the base of sulphur or silicium (silicon ?)) but that would probably not walk around and think about outer space.

The distances are huge. It's not just down to the chemist you know :-), and communication speed is limited and range as well by transmitter power / size of receiver. You are most probably right to assume that it is very improbable we could become aware of "somebody else" in the near/medium future.

 

[Green Baron]

Possible prebiotic forming of RNA / RNA World Hypothesis:

http://science.sciencemag.org/content/352/6287/833

It would be so cool if the first steps weren't as impossible as sometimes thought :-)

 

Edited July 3, 2016 by Green Baron

[PB666]

1 hour ago, Green Baron said:

Possible prebiotic forming of RNA / RNA World Hypothesis:

http://science.sciencemag.org/content/352/6287/833

It would be so cool if the first steps weren't as impossible as sometimes thought :-)

 

I think you putting the cart before the horse. BTW in our current world RNA is the least stable of the three common heterobiopolymers. It has a half-life in the environment of a few seconds. DNA has been recovered almost 100000 years in age, and fully intact collagen has been extracted in bone. The basic problem with RNA is that it has to have a cosiderable amount of polypeptide protection to survive.

OK i agree that RNA as a information biopolymer is prolly how life starts, but the first life form that creates an effective RNAase has a doomsday weapon that could kill life even if it went extinct. They have found fully functional RNAses in the environment that were a few thousand years in age. Going from an RNA world tona DNA world were RNA is used locally as a translation and regulatory  facility is a difficult step. If some thing were to terminate life in the process, RNAses could remain around after inhibiting the restart of life. 

Getting to that first step is not hard, I concede that, the progression is difficult and requires a number of permissive scenarios. 

[Green Baron]

 

That's indeed the main criticism on the RNA World Hypothesis. I personally just find it more conclusive in terms of step-by-step than "Metabolism First", which leads to the hen/egg-problem.

Also, those geoscientists should start to hand over a few reesonable early-surface scenarios. In the moment we're stuck with "surface covered with water, no continents, heavy volcanism and every other day a meteorite" ...

[KerikBalm]

RNA is quite stable in an RNase free environment. I routinely resuspect RNA in nothing other than water, and use it through many free & thaw cycles before the RNA is noticeably degraded in my Northern Blots..

A protein RNase would imply the existence of life with ribosomes and nucleic acid encoding amino acid sequences... this may or may not have come after the advent of cellular life. If the RNA is encapsulated in a lipi membrane with selective transport across the membrane... then RNases in the environment aren't such an issue.

After all... there are plenty of RNA genomes around today... as far as we know they are restricted to viruses, but it illustrates the point. RNA is plenty stable enough as a genome and encapsulation with either a lipid membrane or protein coat would be suffienctto stop RNases from being a "doomsday weapon"

any organism making a promiscuous RNase would have to have its own defense against it, or it would wipeitself out before much of the RNase was made.

While modenr RNases are very stable... they still won't last forever, who knows how stable the first ones were? There is selection pressure to make them more stable, so surely they've evolved to be very stable... so its reasonable that the first ones weren't as stable/

and these RNases wouldn't spread worldwide and wipe out all non-cellular self replicating RNA "life" without continuous production.

The timing of many events is poorly supported (enclosure in a lipid membrane)... but it seems one would have a proto-ribosome before one would have complex proteins, and one would have RNA genomes before one had protein DNA polymerases.

So, I'm sticking by the RNA world hypothesis. RNA is at the center of it all. You can replace many of the functions of amino acids with nucleic acids. You can replace many of the functions of DNA with RNA... but you can't make the system work without RNA.

That isn't to say there couldn't have been multiple very interesting prebiotic chemistry processes happening in parallel, but it would have been the diverse functions of RNA that probably lead to life or something very close to life that then incorporated these other chemistries (lipids, amino acids, deoxyribose, etc)

[PB666]

31 minutes ago, KerikBalm said:

That isn't to say there couldn't have been multiple very interesting prebiotic chemistry processes happening in parallel, but it would have been the diverse functions of RNA that probably lead to life or something very close to life that then incorporated these other chemistries (lipids, amino acids, deoxyribose, etc)

I think that there were many parallel prebiotics. But first. . . . . . .

RNA stability in a testube with no minerals,mgeneral in a treated DPHC water source, in a lab, where you can plop it in a minus twenty degree freezer is not like being in a world with all kinds of chelatable ions, clays, sticky thing stabilize RNA sometimes and many times it makes the polymer bond less stable, certain structures more likely to be cleaved. Highly durable RNAses are not just produce by one species here and there, species produce many kinds of RNases and a great many produce highly stable RNAses. Some of the most 'ancient' are combinations of RNA and small polypeptides.

There is one particular critter that is going to be a real problem with RNA. The logic here is that free phosphate has a problem, we can see the problem olong the coast of Florida, in natures it exist at very low concentration of sea water, not just any sea water, but sea water that has abundant plant life. Very quickly phosphate goes down, but not by bioaccumulation. During a primative sea there would have been alot of partially reduced metals . . . . . copper I, iron I and II. The only metals that become fully oxidized are sodium, magnesium, etc. Sulfite/sulfate/sulfide was also not so oxized.. But the moment the cyanobacterium start fixing CO2, redox rises, then local phosphate concentration starts to drop, sulfate concentrations rise. Phosphate is a trivalent ion, heat it up to about 60'c and it pretty much precipitates on anything except the monovalent cations. So that free soluble phosphate drops around photosynthetic redox potentials, and where the worlds greatest phophate reserves, such as in UTah, are found before the GOE. These cyanobacterium can fix nitrogen if it disaapears, but not phosphate, they require phosphate in the ppb range to fix nitrogen, this is probably and evolved efficiency, in ancient survival required recycling linked phophate. and as you see large outbreaks of cyanobacterial nitogen fixation are wholey not good for other life forms, their nitrogen forming cysts are filled with some of the most toxic organic known to eucaryotes. When they went through the local sensitive biotypes, of course they are going to chew up RNA from the dead organisms for phosphate. So right within one phyla you have a virtually perfect sustained block for any new RNA based life from ever developing, RNA nor phosphate is stably available at the concentratins required for life to form up until humans arrive and produce sustained agriculture. Yeah,msure volcanoes belch it out from time to time, huge dieoffs can create conditions were its stable, but not long enough for life to evolve. 

There is a scenario whereby cyanobacterium killed off all life, and blocked eucaryotes from evolving. But fortunately for us archaean were very diverse, and the predator can become the prey, Eucaryotes split the role of phototrophs and quelled the big cycles. Not only ridding the world of RNA based nonvirals but both DNA bearing alternatives. As we know however archae can live in very bizarre circumstances including places where those poisons are not stable. So once archean communities get established with stable DNA inheritance, the cyanobacterium cannot kill them off, and you see the rise of obligate commensal communities. 

But that actually defines the problem. When we talk about evolution and when we specifically talk about a transition between a probable bioneogenesis and evolution that can be monitored via paleontologicalnand molecular cladistics, we are talking about the natural history of the Earth and not the natural history of any other world, maybe without a comparable in the universe. Using our particularly flaw observations of that process, including my own errors, does not ultimately dissolve the critical problem, we dont know well our early natural history.

When we combine that and an observation of one, not just sentient, but complex living world, and only one, which we, the one, are trying to create a statistic, we begin either ignoring our existence in the universe, or biasing like hades the argument. I am not an advocate of my knowledge, I have presented many links i disagree with. I revert to Socrates, we don't know what we think we do .    Everything else is a pretext to speculation. 

Science is about the process. 

 

[Green Baron]

 

The chemism of the *real* primordial ocean and atmosphere at the time the RNA is supposed to have formed (more or less directly after that ocean had formed) is not known. That is because there are (nearly) no traces left of that timespan of almost 500my (the Hadean).

I just browsed through the wikipedia article and must say that it's rather daring to give out details on atmospheric or oceanic composition from 0 to 4by. The first rocks we can look at are already metamorphic, which means they have gone through a process of orogeny. At that time, a little less than 500my after solidification of the crust, the above process had happened long ago, the "cheese was eaten" (german saying).

The whole plate tectonic was already up and running, beginning with a totally water covered basaltic surface and had probably already completed a "wilson cycle" (no supercontinent of course), the ocean floor exchanged at least once (*). There are only a few zircons from the time before that. Temperature is unclear (some say warm and others cool :-)), but microcontinents (cratons) and an ocean existed.

Until someone corrects me ...

(*) Tectonic processes are assumed to have been much faster than they are today cause at the end or the archaean 70% of todays continental crust was fromed.

 

Edited July 3, 2016 by Green Baron

[PB666]

36 minutes ago, Green Baron said:

 

The chemism of the *real* primordial ocean and atmosphere at the time the RNA is supposed to have formed (more or less directly after that ocean had formed) is not known. That is because there are (nearly) no traces left of that timespan of almost 500my (the Hadean).

I just browsed through the wikipedia article and must say that it's rather daring to give out details on atmospheric or oceanic composition from 0 to 4by. The first rocks we can look at are already metamorphic, which means they have gone through a process of orogeny. At that time, a little less than 500my after solidification of the crust, the above process had happened long ago, the "cheese was eaten" (german saying).

The whole plate tectonic was already up and running, beginning with a totally water covered basaltic surface and had probably already completed a "wilson cycle" (no supercontinent of course), the ocean floor exchanged at least once (*). There are only a few zircons from the time before that. Temperature is unclear (some say warm and others cool :-)), but microcontinents (cratons) and an ocean existed.

Until someone corrects me ...

(*) Tectonic processes are assumed to have been much faster than they are today cause at the end or the archaean 70% of todays continental crust was fromed.

 

 

There is a huge section of rock that extends from the rocky mountains up into new foundland and northern canada that is as old as life itself.   There are a number of geoloigc formations in the northern US wher yoiu can basicall y travel down for the GEO into basically primordial earth. 

For example it has the owiyukuts, Red creek quartzite, Jesse ewing formation, uinta mtn formation, Farmington canyon complex, all of which are precambian and some are preprot. 

You get alot of this stuff on the wyoming utah border, its an interesting drive to say the least, the rock goes from yellow to ,' blood red'   The difference is that in Canada alot of this stuuf is buried under ages of silt and highly stabilizing peat formation, as you get close to yellwstone you get both uplift and surface compression. 

The phosphoria firmation old itself is phosphorous rich sedimentary rock that was dislodged and separated from other components and resedimented, along with permian fish bone and other components. In areas its 420 meters thick, so that represents a pretty large area of preferential phophate deposition and recollection. According to the local posting close to UTah some of the embedded basalt and was as old as the plate itself, so it had a breccia composition, the originating formation is long gone. But larger amounts are early shalestone, the type that they are producing shale gas from in parts of the us. Obviously this is not neogenic methane, so its much older than cellular life. It helps in see this stuff to be old, and take it slow, i can sit for about an hour driving and need to stop and the best places are the state run info rest stops. The scenery in this region is spsctacular particularly in a evening sun you get these fantasic reds and alternating red/green layers. 

 

[Green Baron]

Yeahyeah :-),

there are some old shields in Canada dating 2.5 to 4.0by or so, i don't have the exact numbers right now. That's the oldest part of the north american continent and belong to the oldest rocks on earth. Everything else is younger, red creek quartzite late archean and Jesse ewing formation middle proterozoic, uinta late proterozoic, too young by 1,5-3by. That's already eurcayotes' times ;-)

All these very "old shield rocks" like those in Canada are highly metamorphic and tell little about the environment. There are no rocks from the time when RNA is supposed to have formed and hence no record of the conditions of ocean or atmosphere at that time (that would be hadean, 4.5 to 4by). Only a few zircons ... and assumptions.

Because of that chemist's can speculate of what the primordial soup was like.

Hope we're talking not totally different languages here and always ready for correction :-)

Edit: it is because that with the forming of the ocean and a few hundred my time the basis for life is ready, my opinion is that microbes are "not a big deal".

 

Edited July 3, 2016 by Green Baron

[PB666]

Very little survives the late heavy bombardment; however, there is some hope with the thinning of the permafrost and the peat bogs in central canada you can have some old life layers but only along the littoral stand, not on the exposed surface. But the brecca and neogenic chert within other formation might inform on the actual RNA potency, but not RNA or DNA themselves.

There is a saying about DNA, dry and cold, lots of reducing agents, unless you have trapped gas layers in the older formations, RNA does not survive. This is relativley independent of the sugar moeity. The nucleotides are susceptible to oxygen free radicals. Cytosine undergoes deamination, the prcense of any kind of microbes, even at a distance will result in degradation. Even at the top and bottom of oil formations you have the enzymes capable of degrading RNA.  

There is DNA inside your  bone and teeth that survive the lifetime of the bone or tooth that resultred from apoptosis in the ontology of every complex eucaryote, be that as it may the ambient fluids in a wet environement, even slighlty moist and the presence of microbes connected to that environment, even long dead microbes suffice to degrade polynucleotides after a few 100,000 years. 

[Green Baron]

[sarkasm]Advances in evolution[/sarkasm]: Drake equation evolved to version 2.0

to include abiogenesis.

The link i had yesterday is broken today, i'm sure it'll be someplace else soon(tm).

 

Edited July 5, 2016 by Green Baron

[PB666]

http://www.space.com/33374-odds-of-life-emerging-new-equation.html

[PB666]

https://www.washingtonpost.com/news/morning-mix/wp/2016/08/03/a-new-reason-why-we-havent-found-alien-life-in-the-universe/?tid=pm_pop_b

 

Basically probability of life is a function of the age of comoving space time, the earth is an early arriver for life, the chance of life of our complexity existing at any point in time increases from zero for billions of years and then begins its climb, that probability has yet to peak.

The flip side for this, is that in many supergalaxies, new star formation has collapsed before the best windows have opened, and consequently may not have life at all. Where as in a few billion years smaller galaxies might be abundant with sentient life.

Edited August 3, 2016 by PB666

[ElJugador]

@PB666

As may have been pointed out earlier, and I have already said elsewhere: Due to the (very) high biases our detection and observation methods impose to larger worlds and smaller suns on our data, your severe reliance on it as a chokepoint is automatically highly suspect. Imagine if we were nearsighted, hard-of-hearing anthropologists from some completely different civilization, and we visited a favela in Rio for a few minutes. You're telling us, in essence, that all of human civilization and Earth as a whole must have, ipso facto, about the same living conditions, language, demographics, culture, climate, geology, and terrain.

I'm sorry, and I'm almost certainly going to come across as naive to you, but I... don't buy it. (I also don't really buy the Rare Earth hypothesis, either, but my cute little analogy for that will come another time.)

 

Edited August 3, 2016 by ElJugador